4 month old flips on his tummy

My 4 month old just started flipping over on his tummy....ALL THE TIME. He hasn't figured out how to turn himself back over yet...and he gets frustrated and cries after about 5 minutes. It's ok while he's awake, I let him practice his "tummy time" as much as possible, but when I put him down to sleep, he keeps flipping over and crying. This is especially hard at night, I have to keep flipping him back over....what do I do??? My husband and I aren't getting any sleep. HELP!:crying:

He will learn to roll back pretty quickly. This won't last very long.

I think you can buy safety sleeper things that keep baby in place. I haven't used one, but maybe check out your local baby store and ask in the meantime :)